Remove typeguard PyPy tests (python#463)

This one has been flaky for a while (since July I think), but has
recently started failing pretty consistently

Author: hauntsaninja

.github/workflows/third_party.yml

@@ -186,7 +186,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "pypy3.10"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps: